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Gateway

The Gateway is a receive-only SMTP server designed for QA and testing environments. It accepts incoming emails, validates authentication (SPF, DKIM, DMARC, reverse DNS), and stores them with configurable retention.

Key Capabilities

Section titled “Key Capabilities”
  • SMTP Reception: Receive-only server on port 25 with automatic TLS via Let’s Encrypt
  • Email Authentication: Full SPF, DKIM, DMARC, and reverse DNS validation on every message
  • Web Interface: Angular-based UI at /app for viewing emails and authentication results
  • REST API: Programmatic access to emails with auto-generated API keys
  • Configurable Retention: Default 7-day TTL, adjustable via environment variables

Architecture

Section titled “Architecture”

The Gateway runs as a single container with two integrated components:

  • Backend (NestJS): SMTP server, certificate management, REST API, serves the frontend
  • Frontend (Angular): Email viewer, authentication results display, inbox management
┌─────────────────────────────────────┐
│  Frontend (Angular)                 │
│  - Served at /app                   │
│  - API calls via /api               │
└──────────────┬──────────────────────┘
               │ HTTP(S)
┌──────────────▼──────────────────────┐
│  Backend (NestJS)                   │
│  - REST API (/api)                  │
│  - SMTP Server (port 25)            │
│  - Let's Encrypt certificates       │
└─────────────────────────────────────┘

Requirements

Section titled “Requirements”
  • Public IP with ports 25, 80, and 443 accessible
  • DNS control for your testing domain (A record + MX record)
  • Docker (recommended) or Node.js 18+
Section titled “Links”

Next Steps

Section titled “Next Steps”